Gasoline additive



United States Patent 3,413,105 GASOLINE ADDITIVE Curtis P. Parsons and Charles T. Pumpelly, Midland,

Mich, assignors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Filed Jan. 3, 1966, Ser. No. 517,898 2 Claims. (Cl. 4472) This invention relates to new gasoline fuel compositions containing a new additive which reduces the emission of hydrocarbons in the exhaust of internal combustion engines operating on the fuel.

Atmospheric contamination by automobile exhaust is a great and growing problem toward the control of which increased attention is being directed.

Additives such as alcohol, diethyl ether and nitromethane have been added to gasoline for various reasons and many of them produce a reduction in the hydrocarbon content of the exhaust. This reduction, however, is little if any more than can be accounted for by the oxygen in the additive, i.e., these additives merely serve as an expensive source of oxygen, and the same reduction in hydrocarbon content of the exhaust can equally well be attained by merely adjusting the carburetor to provide a leaner fuel mixture (higher air-to-fuel ratio). While such leaner fuel mixtures reduce the hydrocarbon content of the exhaust, they are objectionable for other reasons, such as excessive rate and temperature of combustion, burning of valves, etc.

According to the invention, the addition to gasoline of a small proportion of dibromofluoronitromethane (referred to hereinafter as DFN) substantially reduces the hydrocarbon emission of engines using the improved fuel, this improvement being far greater than would be expected the leaning effect of the oxygen contained in the additive. Thus, the engine can be operated with a normally rich fuel mixture and yet emit an exhaust having the low hydrocarbon content characteristic of that produced with lean fuel mixtures.

The amount of DFN can be varied widely, depending 3,413,105 Patented Nov. 26, 1968 N o additive Additive 002 (percent) 11. 1 11. 4 02 (percent) 0.62 0. 94 N 2 (percent)- 82.8 80. 6 1. Zero 412 290 We claim:

1. A gasoline fuel composition for internal combustion engines containing a minor proportion, effective to reduce the hydrocarbon content of the exhaust of an internal combustion engine operated on said fuel, of dibromofiuoronitromethane.

2. The composition of claim 1 wherein the proportion of dibromofluoronitromethane is 1-5% by volume.

References Cited UNITED STATES PATENTS 2,274,666 3/1942 Clarke et a1. 44-57 2,583,048 l/ 1952 Hannum et a1. 44-72 2,838,387 6/1958 Rudel 44-79 3,133,844 5/1964 Royer et al. 149-89 3,159,686 12/1964 Burk et al. 260644 DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner. 

1. A GASOLINE FUEL COMPOSITION FOR INTERNAL COMBUSTION ENGINES CONTAINING A MINOR PROPORTION, EFFECTIVE TO REDUCE THE HYDROCARBON CONTENT OF THE EXHAUST OF AN INTERNAL COMBUSTION ENGINE OPERATED ON SAID FUEL, OF DIBROMOFLUORONITROMETHANE. 